Andritz Hydro

Simulations of spherical valve for the main inlet of a hydroelectric plant confirms the safety of the entire assembly and the single components.

Problem:

In a hydroelectric plant, the main inlet valve (MIV) must guarantee functionality and reliability while properly interrupting the water flow that arrives from upstream at high pressure. Andritz Hydro uses the classical design of a spherical MIV made by casting components.

A smart solution was selected using forgings (for high structural quality components) assembled by bolts with controlled tightening, thus removing most of the welds to reduce manufacturing steps and control costs. Hence, an in-depth structural analysis of the entire valve was very important to verify the effectiveness of each bolt coupling and to optimize component thicknesses by parameterizing the main dimensions of the design.

Solution:

In this analysis, the submodeling technique was fundamental. The ability to perform submodeling analysis directly in ANSYS Workbench allowed Andritz to speed up the design steps and maintain tight deadlines by focusing on the optimal point between structural safety and cost-to-design.

The structural analysis started from the “father” model of the entire valve with simplified components and load and boundary conditions equivalent to realistic working conditions (including some fictitious worst-case events). For the thickness optimization of the main components, Andritz developed a system of parameterizations between the different Workbench analyses to accelerate and optimize the verification operations. The most complex and important zones of the valve were created with submodel displacements from the father model applied to the coherent cut-boundary surfaces.

Business Benefit:

Customer interest started with the demonstration of the first valve; sales of the new bolted MIVs increased rapidly. Andritz reduced production costs by eliminating most of the welds and reducing the weight, which decreased the cost of the components. Finite element calculations to optimize thickness permitted the production of a series of valve sizes with controlled structural properties.

Parameterization reduced the time to solution of these simulations, which cut design time and time to market. The decreased costs allowed Andritz to reduce the sales price by nearly 30 percent.

Software used:

  • ANSYS DesignModeler
  • ANSYS Mechanical